I have a month to paint before move-in, so I could really use some input! Your homes are all so lovely, and I need your eyes!

I'm going for a neutral, but inviting, contemporary look, without it all being light tan and nondescript. The floorplan is very open, so I want to break up the space without making it look too much smaller.

The floors are also dark, so....

So far, I figured I'd paint the majority of the downstairs and stairwell cream (Behr Mineral or Philadelphia Cream), accenting with a medium-dark khaki/taupe/greige (Behr Toffee Crunch or Gobi Desert or SW Gallery Buff) in the kitchen/dining area. Ultra pure white semigloss trim, and cabinets.

My questions are:
1. Should I bring in a third color downstairs or accent more walls?
2. Should I use the khaki in the upstairs hallway? I want the house to really flow, and the 3 bedrooms so far will be warm gold, pink, and lt blue-gray. So you can imagine my problem!!!

Help greatly appreciated!!